Proposed studies are based on the premise that events involved in the regulation of neurotransmission are involved in the modulation of behaviors which are disrupted in psychosis. In this regard we plan to continue studies of the role of the central dopaminergic system, cholinergic and serotonergic systems in the mediation of psychotic behavior. The interaction of dopamine with mescaline and amphetamine will be further studied to determine the possible role of dopamine in the mediation of behaviors affected by these drugs. We have identified and characterized a mammalian enzyme which can catalyze the formation of hallucinogenic derivatives of serotonin has been described by others. We have found both of these enzymes in human blood cells. the relationship of enzyme activity in blood to that in brain will be studied in lower animals. Enzyme activity in blood cells from psychotics and controls will be assessed and results compared with their behavioral state. Techniques for the acquisition of quantitative behavioral data will be utilized for comparison with laboratory findings.